Preheat oven to 425°F (220°C). In a greased 9 x 13-inch baking dish, whisk together the broth, marinara sauce, pesto, and garlic powder. Stir in the uncooked pasta, beans, and sundried tomatoes. Cover tightly with aluminum foil and bake for 30 minutes.
Uncover; stir the pasta gently with a fork. At this point you should check the pasta to make sure that it is al dente (still firm, but with a tender bite). I have had good luck with the 30-minute cook time; however, some readers have noted that it required 5-10 more minutes. If it’s still too hard after 30 minutes, just cover the dish and return it to the oven until the pasta is al dente. Then move on to the next step.
Stir in the spinach leaves and sprinkle the cheese over top.
Bake uncovered for about 5 more minutes, or until the cheese melts and the pasta is tender.
Garnish with freshly grated Parmesan or chopped fresh herbs, if desired.
